*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

.wrap ul li{
    list-style-type: none; 
}
.wrap a{
    text-decoration: none;
}
.wrap{
    width: 100%;
    margin: 0 auto;
}
.menu a{
    color: #2d3436;
}
.menu>li{
    padding: 10px;
    float: left;
    width: 25%;
    text-align: center;
    background-color: #00b894;
    font-size: 16px;
    transition: .9s;
}
.boa:hover .box{
    height: 200px;
}
.box{
    height: 0;
    overflow: hidden;
    transition: .5s;
    left: 20px;
    background-color: transparent;
}
.box li{
    height: 40px;
    text-align: center;
    line-height: 46px;
    font-size: 15px;
}
.clearfix:after {
    content:""; 
    display: block; 
    clear:both; 
 }